SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '6121c32a8524f05db9e70387069263116397d636dfd75da11d68833a49b34970' 
  AND token = '/mCmdZGigUMg3lQlaZUH/DjXumaa+cO2r984iQVkLCM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}